Optimal Duration of Treatment in Surgical Patients With Calf Venous Thrombosis Involving One or More Veins

Rivaroxaban treatment for six weeks versus three months in patients with symptomatic isolated distal deep vein thrombosis: randomised controlled trial

OBJECTIVE

To compare two different treatment durations of rivaroxaban in patients with symptomatic isolated distal deep vein thrombosis (DVT).

DESIGN

Randomised, double blind, placebo controlled clinical trial.

SETTING

28 outpatient clinics specialising in venous thromboembolism.

PARTICIPANTS

402 adults (≥18 years) with symptomatic isolated distal DVT.

INTERVENTIONS

After receiving standard dose rivaroxaban for six weeks, participants were randomly assigned to receive rivaroxaban 20 mg or placebo once daily for an additional six weeks. Follow-up was for 24 months from study inclusion.

MAIN OUTCOMES MEASURES

The primary efficacy outcome was recurrent venous thromboembolism during follow-up after randomisation, defined as the composite of progression of isolated distal DVT, recurrent isolated distal DVT, proximal DVT, symptomatic pulmonary embolism, or fatal pulmonary embolism. The primary safety outcome was major bleeding after randomisation until two days from the last dose of rivaroxaban or placebo. An independent committee adjudicated the outcomes.

RESULTS

200 adults were randomised to receive additional rivaroxaban treatment and 202 to receive placebo. Isolated distal DVT was unprovoked in 81 (40%) and 86 (43%) patients, respectively. The primary efficacy outcome occurred in 23 (11%) patients in the rivaroxaban arm and 39 (19%) in the placebo arm (relative risk 0.59, 95% confidence interval 0.36 to 0.95; P=0.03, number needed to treat 13, 95% confidence interval 7 to 126). Recurrent isolated distal DVT occurred in 16 (8%) patients in the rivaroxaban arm and 31 (15%) in the placebo arm (P=0.02). Proximal DVT or pulmonary embolism occurred in seven (3%) patients in the rivaroxaban arm and eight (4%) in the placebo arm (P=0.80). No major bleeding events occurred.

CONCLUSIONS

Rivaroxaban administered for six additional weeks in patients with isolated distal DVT who had an uneventful six week treatment course reduces the risk of recurrent venous thromboembolism, mainly recurrent isolated distal DVT, over a two year follow-up without increasing the risk of haemorrhage.

TRIAL REGISTRATION

EudraCT 2016-000958-36; ClinicalTrials.gov NCT02722447.

Outcomes of isolated distal thrombosis managed with serial compression ultrasonography

BACKGROUND

Isolated distal deep vein thrombosis (IDDVT) is a common subtype of deep vein thrombosis (DVT). Consensus guidelines provide conflicting recommendations for IDDVT management; some recommend anticoagulant treatment, while others suggest serial compression ultrasonography (CUS) monitoring for patients not at "high risk" of proximal extension. The purpose of this study was to describe outcomes of serial CUS-monitored IDDVT and identify risk factors for proximal thrombus extension or anticoagulant treatment initiation.

METHODS

A retrospective descriptive study was conducted using electronic data from University of Utah Health. Adult subjects with objectively confirmed, serial CUS-monitored IDDVT were included. Subjects were followed for 30 days for occurrence of a composite outcome of proximal thrombus extension or anticoagulant treatment initiation. Descriptive statistics were used to summarize characteristics of the study population. Characteristics were compared across outcome groups using inferential statistics.

RESULTS

A total of 182 subjects were included, with 53 subjects (29.1%) experiencing the composite outcome. Of these, 12 (22.6%) experienced proximal thrombus extension and 41 (77.4%) initiated anticoagulant treatment. A prior history of venous thromboembolism (VTE) was significantly higher in those who experienced the composite outcome than in those who did not.

CONCLUSIONS

Our results suggest that 70% of patients with serial CUS-monitored IDDVT did not experience thrombus extension or require anticoagulant treatment within 30 days of diagnosis, regardless of risk factors for proximal extension. Serial CUS monitoring may be a useful management strategy for IDDVT. A history of VTE may identify patients more likely to experience proximal thrombus extension or require anticoagulation.

Significance and management of isolated distal deep vein thrombosis

PURPOSE OF REVIEW

Management of isolated distal deep vein thrombosis (IDDVT) remains controversial. We summarize recent studies regarding the natural history of IDDVT as well as pertinent therapeutic trials. We also provide our management approach.

RECENT FINDINGS

IDDVT is more commonly associated with transient risk factors and less often associated with permanent, unmodifiable risk factors than proximal DVT. IDDVT has a significantly lower risk of proximal extension and recurrence than proximal DVT. Cancer-associated IDDVT has a similar natural history to cancer-associated proximal DVT, with substantially less favourable outcomes than noncancer-associated IDDVT. Anticoagulant treatment reduces the risk of proximal extension and recurrence in IDDVT at the cost of increased bleeding risk. Intermediate dosing of anticoagulation may be effective for treating noncancer-associated IDDVT in patients without prior DVT.

SUMMARY

IDDVT with a transient risk factor can be treated for 6 weeks in patients without a prior DVT. Unprovoked IDDVT in patients without malignancy can be treated for 3 months. Outpatients without malignancy or a prior DVT can be left untreated and undergo surveillance compression ultrasound in one week to detect proximal extension, but few patients opt for this in practice. Cancer-associated IDDVT should be treated analogously to cancer-associated proximal DVT.

Calf Vein Thrombosis Outcomes Comparing Anticoagulation and Serial Ultrasound Imaging Management Strategies

OBJECTIVE

To compare outcomes among patients with calf deep vein thrombosis (DVT) stratified by management strategy because distal or calf DVT is said to have low rates of propagation, embolization, and recurrence and, as such, guideline recommendations include provisions for serial imaging without treatment.

PATIENTS AND METHODS

Consecutive patients with ultrasound-confirmed acute DVT involving the calf veins (January 1, 2016, to August 1, 2018) were identified by scrutinizing the Gonda Vascular Center Ultrasound database. Patients were segregated into 2 categories depending on management strategy; anticoagulation vs serial surveillance ultrasound without anticoagulation. Outcomes including venous thromboembolism (VTE) recurrence, bleeding, death, and net clinical benefit were compared by treatment strategy.

RESULTS

There were 483 patients with calf DVT identified; 399 were treated with anticoagulation therapy and 84 were managed with surveillance ultrasound. Patients in the surveillance group were older (70.0±13.9 vs 63.0±14.9 years; P<.001) and more likely to have had a recent hospitalization (76.2% [64/84] vs 45.4% [181/399]; P<.001). Common reasons for choosing ultrasound surveillance included guideline prescriptive (58.3% [49/84]), active bleeding (21.4% [18/84]), and recent surgery (17.9% [15/84]). The VTE recurrence composite was lower for patients treated with anticoagulants (7.3% [29/399]) compared with surveillance (14.3% [12/84]; P=.04). The DVT propagation was less frequent in the treated group (2.8% [11/399] vs 8.3% [7/84]; P=.01). There was no difference in bleeding or mortality outcomes by management strategy. Net clinical benefit (VTE recurrence plus major bleeding) favored anticoagulant therapy (9.8% [39/399] vs 20.2% [17/84]; P<.01).

CONCLUSION

Patients with calf DVT treated with anticoagulants had significantly better outcomes compared with those managed by a strategy of serial ultrasound surveillance without increasing bleeding outcomes.

Risk Factors and Anticoagulation Therapy in Patients With Isolated Distal Deep Vein Thrombosis in the Early Post-operative Period After Thoracic Surgery

Background: Isolated distal deep vein thrombosis (IDDVT) accounts for ~50% of all patients diagnosed with deep venous thrombosis (DVT), but the diagnosis and optimal management of IDDVT remains unclear and controversial. The aim of this study was to explore potential risk factors and predictors of IDDVT, and to evaluate different strategies of anticoagulation therapy.

Methods: A total of 310 consecutive patients after thoracic surgery, who underwent whole-leg ultrasonography as well as routine measurements of D-dimer levels before and after surgery were evaluated. The general clinical data, anticoagulant therapy, pre- and postoperative D-dimer levels were collected. Differences between IDDVT, DVT and non-DVT groups were calculated. Logistic regression analysis was used to analyze risk factors of postoperative IDDVT.

Results: Age and postoperative D-dimer levels were significantly higher in IDDVT group than in non DVT group (p = 0.0053 and p < 0.001, respectively). Logistic regression analysis showed that postoperative D-dimer level was a significant independent predictor of IDDVT even when adjusted for age and operation method (p = 0.0003). There were no significant side effects associated with both full-dose and half-dose anticoagulation regimens. Half-dose therapy was associated with a significant decrease in the requirement for anticoagulation medications after discharge (p = 0.0002).

Conclusion: Age and D-dimer levels after surgery are strong predictors of IDDVT following thoracic surgery. Half-dose therapeutic anticoagulation has the same efficiency in preventing IDDVT progression, is not associated with any additional risks of adverse effects compared to a full-dose regimen, and may be adopted for treating IDDVT patients after thoracic surgery.

Calf deep vein thrombosis: frequency, therapeutic management, early outcomes and all-causes mortality in a cohort of hospitalized patients

BACKGROUND

Isolated distal deep vein thromboses (IDDVT) are frequent; however, their optimal management is still controversial.

METHODS

We performed a retrospective study on inpatients undergoing ultrasound for suspected deep vein thrombosis (DVT) or with a particular risk profile, during 2016. This study aimed to assess the frequency of proximal deep vein thromboses (PDVT) and IDDVT; to evaluate therapeutic management and identify variables associated with early outcomes and mortality among IDDVT patients; to compare all-causes mortality between subjects with PDVT and IDDVT.

RESULTS

Among 21594 patients hospitalized in the study period 251 IDDVT and 149 PDVT were diagnosed; the frequency was 1.2% and 0.7% respectively. 19% of IDDVT patients died compared to 25.5% of PDVT subjects (OR=0.72; 95% CI=0.44-1.17; P=0.19). In IDDVT patients, age ≥80, cancer and intracranial bleeding increased the risk of death (OR=2; 95% CI=1.07-3.75, P=0.001; OR=8.47; 95% CI=3.28-21.88, P=0.0000003; OR=2.33; 95% CI=1.18-4.58, P=0.0003). A significant association between intracranial hemorrhage and both proximal extension by using the Fisher's exact test (P=0.031; OR=16.11; 95% CI=0.80-321.2), and composite of propagation to popliteal or to other calf veins (OR=8.28, 95% CI=2.07-33 P=0.001) was observed. Standard anticoagulation significantly reduced the composite of propagation to popliteal or to other calf veins (OR=0.07; 95% CI=0.009-0.61, P=0.007), and all-causes mortality (OR=0.37; 95% CI=0.17-0.8; P=0.02), without a significant increase of bleeding.

CONCLUSIONS

Among inpatients, IDDVT exceeded 60% of DVT. Mortality was not significantly different between IDDVT and PDVT subjects. Intracranial bleeding significantly increased the risk of propagation and death. Although standard anticoagulation decreased both these complications, further targeted studies are needed.

Calf deep vein thrombosis – clinical relevance, diagnostic approaches and therapeutic options

Summary. Isolated distal deep vein thromboses (IDDVT) represent up to 50 % of legs deep vein thromboses (DVT). However, since their natural history is to date unknown, the need to diagnose and treat them is a matter of debate. The diagnostic strategy based on the assessment of pre-test probability and D-dimer demonstrated a scarse efficiency for IDDVT. The choice between a proximal and a complete ultrasonographic approach should be guided by the clinical context, the local expertise and the patient characteristics. Randomized and observational studies have analyzed the need of therapy and compared different regimens of anticoagulation, with conflicting results. Systematic reviews and meta-analyses tend to support the usefulness of an anticoagulant treatment, even if the optimal dose and duration are not still defined. A careful stratification of the patient’s profile, taking into account risk factors for proximal extension, recurrence and bleeding should address the therapeutic approach, which must always be discussed with an adequately informed patient. Further studies aimed to clarify the natural history of IDDVT, and to assess safety and efficacy of lower intensity and shorter duration protocols are urgently needed.

Anticoagulation in Deep Venous Thrombosis: Current Trends in the Era of Non- Vitamin K Antagonists Oral Anticoagulants

:

Anticoagulation therapy is the cornerstone of treatment in acute vein thrombosis (DVT) and it aims to reduce symptoms, thrombus extension, DVT recurrences, and mortality. The treatment for DVT depends on its anatomical extent, among other factors. Anticoagulation therapy for proximal DVT is clearly recommended (at least for 3 months), while AT for isolated distal DVT should be considered, especially in the presence of high thromboembolic risk factors. The optimal anticoagulant and duration of therapy are determined by the clinical assessment, taking into account the thromboembolic and bleeding risk in each patient in a case-by-case decision making. Non-Vitamin K antagonists oral anticoagulants (NOACs) were a revolution in the anticoagulation management of DVT. Nowadays, NOACs are considered as first-line therapy in the anticoagulation therapy for DVT and are recommended as the preferred anticoagulant agents by most scientific societies. NOACs offer a simple route of administration (oral agents), a rapid onset-offset of their action along with a good efficacy and safety profile in comparison with Vitamin K Antagonists (VKAs). However, there are issues about their efficacy and safety profile in specific populations with high thromboembolic and bleeding risks, such as renal failure patients, active-cancer patients, and pregnant women, in which VKAs and heparins were the standard care of treatment. Since the available data are promising for the use of NOACs in end-stage chronic kidney disease and cancer patients, several ongoing randomized trials are currently trying to solve that issues and give evidence about the safety and efficacy of NOACs in these populations.

Treatment of distal deep vein thrombosis

BACKGROUND

The treatment of distal (below the knee) deep vein thrombosis (DVT) is not clearly established. Distal DVT can either be treated with anticoagulation, or monitored with close follow-up to detect progression to the proximal veins (above the knee), which requires anticoagulation. Proponents of this monitoring strategy base their decision to withhold anticoagulation on the fact that progression is rare and most people can be spared from potential bleeding and other adverse effects of anticoagulation.

OBJECTIVES

To assess the effects of different treatment interventions for people with distal (below the knee) deep vein thrombosis (DVT).

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 12 February 2019. We also undertook reference checking to identify additional studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) for the treatment of distal DVT.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials and extracted data. We resolved disagreements by discussion. Primary outcomes of interest were recurrence of venous thromboembolism (VTE), DVT and major bleeding and follow up ranged from three months to two years. We performed fixed-effect model meta-analyses with risk ratio (RRs) and 95% confidence intervals (CIs). We assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We identified eight RCTs reporting on 1239 participants. Five trials randomised participants to anticoagulation for up to three months versus no anticoagulation. Three trials compared anticoagulation treatment for different time periods. Anticoagulant compared to no intervention or placebo for distal DVT treatment Anticoagulation with a vitamin K antagonist (VKA) reduced the risk of recurrent VTE during follow-up compared with participants receiving no anticoagulation (RR 0.34, 95% CI 0.15 to 0.77; 5 studies, 496 participants; I² = 3%; high-certainty evidence), and reduced the risk of recurrence of DVT (RR 0.25, 95% CI 0.10 to 0.67; 5 studies, 496 participants; I² = 0%; high-certainty evidence). There was no clear effect on risk of pulmonary embolism (PE) (RR 0.81, 95% CI 0.18 to 3.59; 4 studies, 480 participants; I² = 0%; low-certainty evidence). There was little to no difference in major bleeding with anticoagulation compared to placebo (RR 0.76, 95% CI 0.13 to 4.62; 4 studies, 480 participants; I² = 26%; low-certainty evidence). There was an increase in clinically relevant non-major bleeding events in the group treated with anticoagulants (RR 3.34, 95% CI 1.07 to 10.46; 2 studies, 322 participants; I² = 0%; high-certainty evidence). There was one death, not related to PE or major bleeding, in the anticoagulation group. Anticoagulation for three months or more compared to anticoagulation for six weeks for distal DVT treatment Three RCTs of 736 participants compared three or more months of anticoagulation with six weeks of anticoagulation. Anticoagulation with a VKA for three months or more reduced the incidence of recurrent VTE to 5.8% compared with 13.9% in participants treated for six weeks (RR 0.42, 95% CI 0.26 to 0.68; 3 studies, 736 participants; I² = 50%; high-certainty evidence). The risk for recurrence of DVT was also reduced (RR 0.32, 95% CI 0.16 to 0.64; 2 studies, 389 participants; I² = 48%; high-certainty evidence), but there was probably little or no difference in PE (RR 1.05, 95% CI 0.19 to 5.88; 2 studies, 389 participants; I² = 0%; low-certainty evidence). There was no clear difference in major bleeding events (RR 3.42, 95% CI 0.36 to 32.35; 2 studies, 389 participants; I² = 0%; low-certainty evidence) or clinically relevant non-major bleeding events (RR 1.76, 95% CI 0.90 to 3.42; 2 studies, 389 participants; I² = 1%; low-certainty evidence) between three months or more of treatment and six weeks of treatment. There were no reports for overall mortality or PE and major bleeding-related deaths.

AUTHORS' CONCLUSIONS

Our review found a benefit for people with distal DVT treated with anticoagulation therapy using VKA with little or no difference in major bleeding events although there was an increase in clinically relevant non-major bleeding when compared to no intervention or placebo. The small number of participants in this meta-analysis and strength of evidence prompts a call for more research regarding the treatment of distal DVT. RCTs comparing different treatments and different treatment periods with placebo or compression therapy, are required.

Experience of a 40-day (6 week) LMWH treatment for isolated distal deep vein thrombosis

Clinical significance of distal deep vein thrombosis (DVT) is important as it can potentially result in pulmonary embolism (PE), DVT extension, DVT recurrence and post-thrombotic syndrome (PTS). Controversy remains about the necessity and modalities of anticoagulation in all distal DVT. Evaluation of the efficiency of a 40-day weight-based low molecular weight heparin (LMWH) treatment in a cohort of 119 consecutive patients with distal DVT. Compression ultrasonography of the lower limb was performed initially for diagnosis as well as at the end of the treatment to identify persistence or resolution of the blood clot. A 3-month follow-up estimated the rates of PE, DVT recurrence, DVT extension, PTS and bleeding. Risk factors for DVT were considered to evaluate a possible correlation between them and the outcomes. In 71.4% of the patients the blood clot was totally dissolved and thrombus persistence was statistically associated with the number of initially involved veins. DVT recurrence occurred in 5% of patients and was also associated with the number of initial clotted veins. DVT extension and PTS rates were present in 1.7% and 3.4% respectively and no patient was diagnosed with PE or bleeding. This retrospective study including a limited number of patients and no control group supports that a 40-day weight-based LMWH treatment after distal DVT seems to be efficient when one single vein is initially affected whereas for multiple vein distal DVT and to avoid potential DVT recurrence, longer than 6 weeks of anticoagulant treatment is required. Our results support safety of the treatment, its potential to prevent DVT extension and the occurrence of PE.

Long-term recurrence of venous thromboembolism after short-term treatment of symptomatic isolated distal deep vein thrombosis: A cohort study

Isolated distal deep vein thrombosis (IDDVT) is a common clinical manifestation of venous thromboembolism (VTE). However, there are only scant and heterogeneous data available on the long-term risk of recurrent VTE after IDDVT, and the optimal therapeutic management remains uncertain. We carried out a retrospective cohort study of consecutive patients diagnosed with symptomatic IDDVT between 2004 and 2011, according to a predefined short-term treatment protocol (low molecular weight heparin (LMWH) for 4–6 weeks). The primary outcome was the occurrence of recurrent VTE. A total of 321 patients were enrolled. IDDVT was associated with a transient risk factor or cancer in 165 (51.4%) and 56 (17.4%) patients, respectively. LMWH was administered for 4–6 weeks to 280 patients (87.2%), who were included in the primary analysis. Overall, during a mean follow-up of 42.3 months, 42 patients (15%) developed recurrent VTE, which occurred as proximal DVT or PE in 21 cases. The recurrence rate of VTE per 100 patient-years was 3.5 in patients with transient risk factors, 7.2 in patients with unprovoked IDDVT, and 5.9 in patients with cancer ( p=0.018). At multivariable analysis, unprovoked IDDVT and previous VTE were significantly associated with recurrent VTE (HR 2.16, 95% CI 1.12–4.16 and HR 1.97, 95% CI 1.01–3.86, respectively). In conclusion, the long-term risk of recurrent VTE after IDDVT treated for 4–6 weeks is not negligible, in particular in patients with unprovoked IDDVT or cancer. Further studies are needed to clarify whether a longer, but definite treatment duration effectively prevents these recurrences.

Anticoagulation in patients with isolated distal deep vein thrombosis: a meta-analysis

Essentials The optimal management of isolated distal deep vein thrombosis (IDDVT) is undefined. This meta-analysis aimed to assess the clinical benefit of anticoagulation for IDDVT. Anticoagulation reduced the rate of pulmonary embolism without increasing major bleeding risk. Recurrent thromboembolism was less common with more than 6 weeks vs. 6 weeks of anticoagulation.

SUMMARY

Background The optimal management of patients with isolated distal deep vein thrombosis (IDDVT), concerning both the need for anticoagulation and its duration, is undefined. Objectives We performed a meta-analysis of randomized and cohort studies in patients with IDDVT to assess the clinical benefit of: (i) anticoagulation versus no anticoagulation; and (ii) anticoagulant treatment for 6 weeks versus for > 6 weeks. Methods The primary outcome of this analysis was recurrent venous thromboembolism (proximal propagation, recurrence of deep vein thrombosis, and pulmonary embolism). Data were pooled and compared by the use of odds ratio (OR) and 95% confidence interval (CI). Results A reduction in the rate of recurrent venous thromboembolism was observed in patients who received anticoagulation relative to those who did not receive anticoagulation (either therapeutic or prophylactic) (20 studies, 2936 patients; OR 0.50, 95% CI 0.31-0.79), without an increase in the risk of major bleeding (OR 0.64, 95% CI 0.15-2.73). The rate of pulmonary embolism was lower in anticoagulant-treated patients than in controls (15 studies, 1997 patients; OR 0.48, 95% CI 0.25-0.91). A lower rate of recurrent venous thromboembolism was observed in patients who received > 6 weeks of anticoagulant therapy than in those who received 6 weeks of anticoagulant therapy (four studies, 1136 patients; OR 0.39, 95% CI 0.17-0.90). Conclusions In patients with IDDVT, anticoagulation (both therapeutic and prophylactic) reduces the rate of recurrent venous thromboembolism and the incidence of pulmonary embolism as compared with no anticoagulation, without an increased risk of major bleeding. Anticoagulation for > 6 weeks should be preferred over shorter durations.

Treatment of Isolated Below the Knee Deep Vein Thrombosis

The natural history of isolated distal deep-vein thrombosis (IDDVT) is still uncertain, as well as the real clinical risks associated with the disease and the need for its diagnosis and treatment. While more and more IDDVTs are diagnosed in everyday clinical practice, their appropriate therapeutic management is, unfortunately, far from straightforward, and different recommendations on how patients with diagnosed IDDVT should be treated are present between expert professionals and even among international guidelines. The present article aims at briefly reviewing the issue of IDDVT therapy in general, particularly focusing on the different approaches to the treatment of the disease that have been suggested by recent guidelines, those that are currently adopted in clinical practice, and necessary future directions.

Pulsatility Index of Popliteal Artery in Patients with Isolated Calf Vein Thrombosis: A Novel Technique for Detecting Thrombosis

BACKGROUND

To investigate the usefulness of popliteal artery spectral doppler findings as a complimentary approach to isolated calf vein thrombosis (DVT).

MATERIAL/METHODS

We included consecutive patients presenting with symptomatic and sonographically proven acute isolated calf DVT. Patients with thrombosis of any other vein were excluded. We classified calf vein into into four main types. We investigated how many of these four vessels had DVT and compared them with respect to the pulsatility index (PI) value of the popliteal artery.

RESULTS

We evaluated spectral doppler characteristics of the popliteal artery on the same side as the isolated calf vein thrombosis as well as on the opposite side. The relationship between PI values of the popliteal artery and the number of thrombosed calf veins was investigated. In patients with 1 and/or 2 thrombosed veins, the mean PI was 6.03±0.54 on the side of cDVT and 5.68±0.39 on the opposite side (p=0.008), respectively. Inpatients with 3 and/or 4 thrombosed veins, the mean PI was 8.05±0.61 on the side of cDVT and 6.34±0.47 on the opposite side (p=0.001), respectively.

CONCLUSIONS

Venous doppler sonography for the evaluation of calf DVT may be limited by patient characteristics such as obesity, edema, and tenderness., Arterial PI can be used as a complimentary technique for the detection of venous thrombosis in such of cases.

Incidence of pulmonary embolism in patients with isolated calf deep vein thrombosis

BACKGROUND

The severity of pulmonary embolism (PE) after isolated calf deep vein thrombosis (C-DVT) is controversial, which leads to inconsistent clinical decision making when treating C-DVT. This systematic review assessed PE frequency and severity in patients with C-DVT.

METHODS

Database searches were completed using MEDLINE and Scopus along with cross-referencing. Two independent reviewers used using rigorous inclusion and exclusion criteria to screen the papers. Data concerning PE and C-DVT characteristics as well as methods of detection were abstracted. Studies reporting combined outcomes for patients with proximal and C-DVT, those with concurrent PE at diagnosis, and retrospective studies not allowing the determination of C-DVT and PE as separate events were excluded.

RESULTS

Of 586 papers that were screened, 21 met inclusion criteria, which included eight randomized clinical trials and 13 prospective cohort studies. There was data heterogeneity among patients, methods of diagnosis, and follow-up. PE diagnosis was often based on ventilation/perfusion scanning, where more recent studies used computed tomography angiography. The PE is usually overestimated because it includes concurrent events. The incidence of PE from isolated C-DVT in our review was 0% to 6.2%. No fatal PEs were reported. No data were found on PE severity and patient outcomes regarding this complication.

CONCLUSIONS

Reported adverse outcomes of PE from C-DVT are infrequent, and clinical severity is unclear. Further studies are necessary to determine the actual risk associated with PE after C-DVT to establish proper treatment.

Systematic review of the complications following isolated calf deep vein thrombosis

Background

A large number of studies have examined the potential complications of calf deep vein thrombosis (DVT). There is no consensus on when or how to treat patients to prevent these complications. This systematic review assessed the rate of proximal propagation, pulmonary embolism, major bleeding and recurrence in patients with isolated calf DVT.

Methods

Database searches of MEDLINE, the Cochrane Library, Scopus, CINAHL and Web of Science were undertaken along with extensive cross-referencing. Two independent reviewers screened the papers using stringent inclusion and exclusion criteria. Included studies were graded on six methodological standards. Data on propagation, pulmonary embolism, recurrence and major bleeding were abstracted.

Results

A total of 4261 papers were found; 15 met the inclusion criteria, including five randomized clinical trials and ten prospective cohort studies. The propagation rate to the popliteal vein or above was around 9 per cent and the rate of pulmonary embolism was close to 1·5 per cent. No studies found anticoagulant therapy to reduce the rate of adverse outcomes.

Conclusion

The literature on calf DVT is heterogeneous, limiting conclusions from data analysis. Adverse outcomes are infrequent and studies do not suggest that they are reduced by anticoagulation.

Management of isolated calf vein thrombosis in cancer patients

The treatment of isolated calf vein thrombosis remains widely debated. This study highlights the characteristics of isolated calf vein thrombosis in cancer patients and compares to isolated calf vein thrombosis in patients without history of cancer. Between July 2013 and April 2014, a retrospective chart review of consecutive patients with isolated calf vein thrombosis was performed recording patient risk factors, ultrasound characteristics of the thrombus, treatment modalities, long-term recurrence of venous-thromboembolism, incidence of bleeding, and mortality. Of 131 patients with isolated calf vein thrombosis, 53 (40.1%) had history of cancer. Isolated calf vein thrombosis occurred at an older age in cancer patients (66.7 vs 58.5 years, p = 0.004). The anatomical characteristics of isolated calf vein thrombosis on ultrasound were comparable in both groups. Isolated calf vein thrombosis in cancer patients was less likely to be treated with anticoagulation (60.4% vs 80.8%, p = 0.018). However, a trend towards higher incidence of bleeding after initiation of anticoagulation for isolated calf vein thrombosis in cancer patients (11.3% vs 6.4%, p = 0.351) was noted. Mortality in cancer patients was higher (37.7% vs 9.00%, p < 0.001) but was unrelated to isolated calf vein thrombosis or its treatment. In conclusion, the risks of bleeding seem to exceed the benefits of anticoagulation in approximately 50% of cancer patients with isolated calf vein thrombosis. The management of isolated calf vein thrombosis does not seem to impact the survival of cancer patients.

Duration of treatment with vitamin K antagonists in symptomatic venous thromboembolism

BACKGROUND

Currently, the most frequently used secondary treatment for patients with venous thromboembolism (VTE) consists of vitamin K antagonists (VKA) targeted at an international normalized ratio (INR) of 2.5 (range 2.0 to 3.0). However, based on the continuing risk of bleeding and uncertainty regarding the risk of recurrent VTE, discussion on the proper duration of treatment with VKA for these patients is ongoing. Several studies have compared the risks and benefits of different durations of VKA in patients with VTE. This is the third update of a review first published in 2000.

OBJECTIVES

To evaluate the efficacy and safety of different durations of treatment with vitamin K antagonists in patients with symptomatic venous thromboembolism.

SEARCH METHODS

For this update, the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched October 2013) and the Cochrane Central Register of Controlled Trials (CENTRAL) 2013, Issue 9.

SELECTION CRITERIA

Randomized controlled clinical trials comparing different durations of treatment with vitamin K antagonists in patients with symptomatic venous thromboembolism.

DATA COLLECTION AND ANALYSIS

Three review authors (SM, MP, and BH) extracted the data and assessed the quality of the trials independently.

MAIN RESULTS

Eleven studies with a total of 3716 participants were included. A consistent and strong reduction in the risk of recurrent venous thromboembolic events was observed during prolonged treatment with VKA (risk ratio (RR) 0.20, 95% confidence interval (CI) 0.11 to 0.38) independent of the period elapsed since the index thrombotic event. A statistically significant "rebound" phenomenon (ie, an excess of recurrences shortly after cessation of prolonged treatment) was not found (RR 1.28, 95% CI 0.97 to 1.70). In addition, a substantial increase in bleeding complications was observed for patients receiving prolonged treatment during the entire period after randomization (RR 2.60, 95% CI 1.51 to 4.49). No reduction in mortality was noted during the entire study period (RR 0.89, 95% CI 0.66 to 1.21, P = 0.46).

AUTHORS' CONCLUSIONS

In conclusion, this review shows that treatment with VKA strongly reduces the risk of recurrent VTE for as long as they are used. However, the absolute risk of recurrent VTE declines over time, although the risk for major bleeding remains. Thus, the efficacy of VKA administration decreases over time since the index event.

Calf muscle venous thrombosis: a review of the clinical implications and therapy

Calf muscle veins have been demonstrated to be one of the most frequent areas that develop deep venous thrombosis (DVT), both as an isolated finding and in combination with proximal DVT. Calf muscle venous thrombosis (CMVT) has been shown to be more frequently associated with localized calf tenderness, and when left untreated, a proportion tend to propagate proximally and may lead to pulmonary embolism. Imaging with duplex venous scanning is fairly sensitive in the diagnosis of CMVT. Treatment recommendations for CMVT are variable with some studies showing clear clinical benefit of anticoagulation therapy and others showing no benefit.

Incidence and predictors of venous thromboembolism recurrence after a first isolated distal deep vein thrombosis

BACKGROUND

Isolated distal deep vein thrombosis (iDDVT) (i.e. without proximal DVT or pulmonary embolism) represents half of all cases of lower limb DVT. Its clinical significance and management are controversial. Data on long-term follow-up are scarce, especially concerning risk and predictors of venous thromboembolism (VTE) recurrence.

METHODS

Using data from the OPTIMEV (OPTimisation de l'Interrogatoire dans l'évaluation du risque throMbo-Embolique Veineux) study, a prospective, observational, multicenter study, we compared, 3 years after an index VTE event and after discontinuation of anticoagulants, (i) the incidence and type of recurrence in patients without cancer with a first iDDVT vs. a first isolated proximal DVT (iPDVT) and (ii) predictors of recurrence after iDDVT.

RESULTS

Compared with patients with iPDVT (n = 259), patients with an iDDVT (n = 490) had a lower annualized incidence of overall VTE recurrence (5.2% [95% confidence interval 3.6-7.6] vs. 2.7% [1.9-3.8], respectively; P = 0.02) but a similar incidence of pulmonary embolism recurrence (1.0% [0.5-2.3] vs. 0.9% [0.5-1.6], respectively; P = 0.83). An age of > 50 years, unprovoked character of index iDDVT, and involvement of more than one vein in one or both legs each independently tripled the risk of recurrence, with the latter then being ≥ 3% per patient-year. Neither muscular vein nor deep-calf vein location of iDDVT nor clot diameter with compression influenced the risk of recurrence.

CONCLUSIONS

After stopping anticoagulants, patients with iDDVT have a significantly lower risk of overall VTE recurrence than did patients with iPDVT but a similar risk of serious recurrent VTE. Age > 50 years, unprovoked iDDVT, and number of thrombosed veins (more than one) influenced the risk of recurrence and may help to define patients at significant risk of recurrence.

Isolated distal deep vein thrombosis: what we know and what we are doing

Thromboses that are restricted to the infra-popliteal deep veins of the lower limbs (isolated distal deep vein thrombosis, IDDVT) are frequently diagnosed in subjects with suspected pulmonary embolism (PE; 7–10%) or DVT(4–15%), accounting for 31–56% of all diagnosed leg DVTs. Despite their frequency, IDDVTs still remain one of the most debated issues in the field of venous thromboembolism (VTE). Conflicting clinical results have resulted in differing opinions on the need to test for IDDVTs and how to treat them. Due to discordant results, the real risk of IDDVT-associated PE is not well established. IDDVTs are associated with (i) lower risk of recurrence when compared with other VTEs, and (ii) fewer late sequelae than proximal DVT. Diagnosis of IDDVT is based on ultrasound examination of all calf veins, which is more operator-dependent and less sensitive than proximal vein examination. A series of studies has shown, however, that a single complete ultrasound strategy in symptomatic patients has comparable clinical results to serial proximal ultrasound, allowing approximately 15% better DVT diagnosis. Optimal treatment of IDDVT is still controversial. Guidelines recommend anticoagulation for 12 weeks, although 6 weeks may be sufficient. There is, however, insufficient data to support the diagnosis and treatment of all IDDVTs, and the necessary criteria to identify subjects at higher risk of complication are lacking. It also seems likely that different approaches may be better for unprovoked or secondary events and for deep or muscle veins. Specifically designed and adequately powered clinical studies addressing the issue of IDDVT need to be urgently undertaken.